/Engine/Source/Runtime/Engine/Classes/Kismet/KismetMathLibrary.h
Order matters when composing quaternions: C = A * B will yield a quaternion C that logically first applies B then A to any subsequent transformation (right first, then left).
The result of multiplication (A * B).
static FQuat Multiply_QuatQuat ( const FQuat & A, const FQuat & B )